The best damage range you can get on looted one handed swords is 71-100 (purchased bastard swords can get up to 81-110 IIRC). I'm not sure about two handed swords (I used the two handed bastard sword from the knight by the castle for quite awhile, but before and after that used one handed swords).
With potentially very good swords you can get the best damage range as well as a lot of other bonuses (my Nobleman's Sword had 4 skill bonuses, for example, as well as vitality and a couple stat bonuses). With lower quality weapons the trade-off may be more noticeable if you reload a few times.
